In technically developed countries, perinatal asphyxia affects 3-5 per 1000 live births with subsequent moderate or severe hypoxic ischaemic encephalopathy (HIE) in 0.5-1 per 1000 live births (Levene 1986). HIE is a major problem worldwide as 10-60% of affected infants die, and at least 25% of survivors have long term neurodevelopmental sequelae (Vannucci 1990). In addition 5-10% of newborns require some kind of assistance to start breathing after birth. The aim of resuscitation and resuscitation monitoring by appropriate diagnostic marker is to prevent death and adverse long term neurodevelopmental impairment.
Until recently the therapy was limited to preventive measures and symptomatic supportive strategies after asphyxia. However, asphyxia, hypoxia and related disorders are potentially treatable disorders which potentially impair memory or other mental functions or physical functions. Recent experimental and clinical study clearly show a benefit of hypothermia as a clinically feasible manoeuvre that improve the outcome of neonates with HIE. It has been shown that a delay of hypothermia reduces the neuroprotective potential or the earlier the therapy is initiated the higher the protective effect. Recent research has shown that using extra oxygen for newborn resuscitation will negatively influence both morbidity and mortality. Oxygen inhibits protein synthesis and/or increases their degradation and also is a potent activator and/or suppressor of a number of genes. Furthermore, it contributes to the regulation of membrane transport, intracellular signalling and the initiation of apoptosis.
In addition, in particular in treatment of decompression sickness occurring after recreational or professional scuba diving, it is common to treat patients with 100% oxygen under hyperbaric conditions in a pressure chamber, in order to get rid of nitrogen excess bubbling out after a decompression accident causing symptoms from skin itching to complete paralysis. A hyperbaric oxygen treatment [HBO] protocol is published in the US Navy Treatment Table 6, which is also used with slight modifications in German (GTÜM) and Austrian (ÖGTH) diving and hyberbaric medical associations. itypical treatment. In this treatment protocols a patient suffering from decompression sickness is intermittently exposed to a maximum pressure of 2.8 bar/2.4 bar (corresponding to a water depth of 18 m/14 m) for up to several hours and repeated treatments over several weeks, if necessary.
Currently, no reliable monitoring of oxygen induced damages, in particular brain damages, during HBO therapy is existing, only the clinical signs of a CNS oxygen toxicity, such as neuromuscular spasms are available.
Accordingly, there is an urgent need for timely treatment and early diagnosis of asphyxia, in particular in newborns, and, as pointed out above, an urgent need for therapy monitoring given e.g. detrimental effects due to excess oxygen administration upon treatment.